Acquired Immunity
| Definition | Problems With Immunizations |
| Illness Creates Immunity | Immunization for Avian Flu |
| Immunizations Create Immunity | Tamiflu |
Definition of Acquired Immunity
Immunity acquired after exposure to a pathogen. Acquired immunity
develops when we acquire antibodies to specific pathogens
in one of two ways. In the first case, we contract an infection,
usually viral, i.e. red measles, chicken pox, German measles
(rubella), or a bacterial infection, i.e. whooping cough
(pertussis). In the second case, we are immunized by vaccines,
usually injected.
- Ilness creates immunity to pathogens. When people contract viral illnesses, i.e. chicken pox, German measles etc. or bacterial illnesses, i.e. whooping cough, they usually developed life-long immunity. Circulating 'memory' white blood cells work together with lymphocytes to create antibodies which persist for long periods and confer immunity to those illnesses.
- Immunizations create immunity by taking part, or in some instances, all of the pathogen for which immunity is desired, and killing it or altering it in such a way that when it is injected or ingested, our body’s innate immune system is activated. Once activated, the protein in the immunization turns on immune cells, stimulating the production of a dizzying number of substances which attach themselves to the invading organism, secreting killing substances to destroy them; blast them with powerful chemicals, eat them up, chew them up and spit them out. In the process, information is sent to lymphocytes and other cells which create antibodies to the pathogen. Then, should the person encounter the pathogen in the future, i.e. German measles, they will be immune and not get ill.
The perfect immunization would create antibodies in sufficient numbers to prevent that infection from occurring and would have no side effects. Unfortunately, this is not usually the case with our current vaccines. Not everyone who receives the vaccine will develop antibodies thus not become immune. For some people, following immunization, a reaction or an illness ensues - often mild but occasionally severe. Earlier, when whooping cough immunization was administered to infants, one of the frequent side effects was seizures. Subsequently, this immunization has been improved and the side effects are fewer. It is likely that other problems exist for some people because often immunizations are preserved with stabilizing ingredients (formaldehyde, mercury and aluminum). One subject currently being debated is a possible link between measles, mumps and rubella (MMR) immunization and autism.
When
scientists, working with the pharmaceutical industry,attempt
to create an immunization for viral illness such as influenza,
they select examples of the flu of previous years and try to
predict which flu will happen that year. If they guess correctly,
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people who receive that immunization should, theoretically,
either not get ill from that virus or have a much less serious
illness.
Unfortunately, often the guesses are wrong. People who have been immunized with that year's influenza vaccine may then contract the flu. Sometimes, while the 'guess' has been accurate at the time it was made (months before the flu season), the immunization will fail to protect as intended because, in the interim, the virus has changed identity enough that the antibodies created by the immunization are not at all, or minimally, effective.
A great deal of attention is now focused on prevention of Avian Flu (H5N1). At the moment however, this virus has not infected people other than agricultural workers who are exposed to birds, or laboratory technicians working with the virus. There have been no cases where the virus has been transmitted from person-to-person.
If scientists therefore create an immunization to this particular virus (H5N1) it could be useful for agricultural workers exposed to infected birds. A vaccine for this particular virus (H5N1) in its current form would likely not protect us if the virus mutates. If this virus changes into a form that passes from person-to-person, it would take months to produce a vaccine effective against the new virus. In the meantime, many people would have succumbed.
So we can't count on medical science to protect us in this way. Our best chance of defeating illness, should a pandemic develop, is to have a strong innate immune system.
flu Tamiflu
(Oseltamvir phosphate - Roche) has recently been introduced and is now being promoted as a possible "help" in dealing with an Avian flu pandemic. In the manufacturer's indications for its use is the statement, "There is no evidence for the efficacy of Tamiflu in any illness caused by agents other then influenza viruses Type A and B. Data on treatment of influenza B are limited." In order to be effective, Tamiflu is required to be administered within 48 hours of the onset of symptoms. This medication has never been assessed in the treatment of a coronavirus (avian flu belongs to this category of viruses as it does SARS). Many clinicians with experience with this medication are unsure of its benefits. There may be only a minor improvement in flu symptoms or perhaps a shortening of symptoms, at best, by about three days (most flu's last about 10 days).
There is also emerging data that some people who take Tamiflu could become quite ill, possibly from the medication. One of the clinical concerns with influenza is the effect it has on diminishing immunity, and the development of subsequent infections i.e. pneumonia which often follow. There have been no studies which report on the effect of Tamiflu on this issue .Taken as a whole, it is hard to imagine that this medication could possibly be of any real benefit. Some skeptics have pointed out that Tamiflu could possibly be a profit making tool promoted by the pharmaceutical industry. It is difficult to know the truth of this. In any case, your best defense against a virus is having strong innate immunity.
